CMS Image issue

I have a very strang image issue. I have some image field in my Template (with all code needed to extend CMS) and when I insert content, I tried to attach some image also, and after choosing one (from my computer or from the file store - it is the same) picture, Silverstripe is like acting some upload for picture.

But after it is finished, I see only an empty field (see screen shot below).

Otherwise I would check if you have write permissions to the "assets/Uploads/" Folder. That can do the trick aswell, cause if you use Safari you won't get an ErrorMsg if you have no permissions to that Folder... Firefox helps out here.